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INSTALLING A MOTORISED SATELLITE DISH This can be a difficult task for a complete beginner so if you are not confident/competent use a professional installer. This is a basic guide with links to further information at the bottom of the page. DISEqC AND USALS The DiSEqC protocol is a standardised set of control codes that are sent from a receiver up the LNB cable to circuitry in the LNB to tell the LNB to do something. DiSEqC protocol is used to control a motor on which you mount a satellite dish. USALS is a program for calculating the positions of satellites in orbit and is capable of an accuracy of 0.1°. Both DiSEqC 1.2 and USALS are widely adopted by manufacturers for motorised satellite dish systems worldwide. When installing the dish for the first time, it only needs to be aligned to 1 satellite as a reference point. A receiver with USALS can then take care of finding the rest. DISH AND MOTOR The site of you dish needs to have a clear line of sight in all directions facing south. No obstacles like tall buildings or trees should be in the way of your dish's rotational field of view southwards. The motor mount fits between the dish and the fixed pole, where a fixed dish is normally fitted to. Your pole should be installed as perfectly vertical as possible. The base unit side of your motor should be clamped securely to your pole. Your dish should then be clamped to the motorised pole on your motor. Your motor inclination and dish elevation settings now need to be set accurately. With a motorised dish, the dish does not rotate on a perfect horizontal axis. It rotates the dish on a slight arc (due to the curvature of the Earth) the motorised pole is bent to achieve this arc rotational effect. Before mounting your motor, make sure it is set a zero (0°) (south). Simply connect it to your receiver and move it to zero (0°). At the base of the motor where it is attached to the pole, there is an inclination mount where you can adjust the “motor inclination”. This inclination mount consists of a hinge bolt and another bolt to lock the inclination of the motor in place. The motor inclination needs to be adjusted according to your latitude. You motor will include instructions on the correct inclination; you just need to find the latitude of your location. The dish needs to be clamped after the bend on your motor pole. Once you have mounted your motor correctly to the pole, you will notice that after the bend of your motorised pole, it is almost vertical. Attach your dish to this section of the pole and clamp it securely. Normally the dish is secured to the motorised pole using U-bolts. The elevation of your dish needs to be adjusted according to the following formula: Dish Elevation = motorised pole offset angle – column declination. The motorised pole offset angle is the angle of the motorised pole after the bend to the motor axis. This angle varies between motor models and is usually 30° or 45° to the motor axis. The column declination is a slight adjustment required to account for the fact that a geostationary satellite is not exactly seen from an angle perpendicular to the polar axis but slightly lower. In the UK this varies between 7.3° at Land's end to 8° in Orkney. It shouldn't be to difficult to estimate the figure for where you are based, alternatively just use a figure of 7.5°. Once you have correctly set your motor inclination and dish elevation and your motor is at zero (south) you should now have the correct elevation for the top of the satellite arc or arc apex. HORIZONTAL ALIGNEMENT The motor installation must be adjusted to point south. To find the correct horizontal alignment of the motor mount, position the motor to a known satellite and adjust the horizontal rotation of the motor installation accordingly. In the UK , probably the best satellite to use as a reference point is Hotbird. This is much easier to do if you have USALS on your receiver. Using the USALS software on your receiver, enter your latitude and longitude. Then instruct the receiver to point your dish to Hotbird. This will position the motor to where Hotbird is expected to be found. Then using a meter, adjust you're the horizontal rotation of your motor installation until you get a strong signal. To ensure you have the correct satellite, tune your receiver into a known channel. A good channel to use is RAI News @ 11.804GHz/V 27500 2/3, it has a strong signal and is broadcast 24 hours a day. Check that you can receive this channel with a good strong signal on the receiver's signal indicator. Also, it would be useful confirmation to do a quick transponder scan. If you do not have USALS installed but only have the DiSEqC system, you will have to position the motor to a known satellite manually. The correct position of a motor is calculated using the following formula: Motor Position = Satellite Position – longitude Note that Eastern longitudes are negative and Western Longitudes are positive. Let us take Swansea as an example. Swansea 's latitude is 4 ° west. Hence the motor position should be: - 13 – 4 = - 17, or 17° East. Set your motor position to 17° East, then rotate your motor installation until you get a string signal using a meter. Again, in the same way using USALS, conform that you have the correct satellite using a reference TV channel. If the motor mount has been installed correctly, you should be able to find all the other available satellites easily. You may need to make slight adjustments to the motor inclination, declination and azimuth for the dish to correctly track the satellite arc. Once you have performed the final adjustments, you are ready for multi-satellite reception.
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